You could paint the brass with that high heat paint.

removing the brass doors would really update this. A decorator friend talked me into painting the interior of our fireplace with very dark, almost black, paint and the outside stone a very dark cherry red. It looks gorgeous now. Kids can't turn on the gas if you remove the key..at least on ours.

I would remove doors. paint the inside of firebox black. install a nice screen from cascade screens. if thoes are gas logs do a "tune up". clean, remove lava rock and embers and install new clean lava and embers....will look fresh and clean...AND updated good luck